Improved control channel monitoring

ABSTRACT

A method for use in a User Equipment configured to operate according to the New Radio (5G) standard, said method comprising: monitoring a control region for mini-slots for a transmission; detecting a start of the transmission; monitoring a control region of said transmission for regular slots; detecting that the transmission has ended; and in response thereto monitoring the control region for mini-slots again.

TECHNICAL FIELD

This application relates to a telecommunications device, a method and acomputer-readable storage medium for improved control channel monitoringand in particular for providing control channel monitoring with adynamic or non-static periodicity.

BACKGROUND

Currently the 5th generation of cellular system, called New Radio (NR)is being standardized in 3GPP. NR is developed for maximum flexibilityto support multiple and substantially different use cases. Besides thetypical mobile broadband use case, also machine type communication(MTC), ultra-reliable low latency communications (URLLC), side-linkdevice-to-device (D2D) and several other use cases too.

In NR the basic scheduling unit is called a slot. A slot consists ofeither 7 or 14 OFDM symbols for the normal cyclic prefix configuration.7 symbol slots are only available for when the subcarrier-spacing is 60kHz or lower. As an example a slot with 7 symbols at 60 kHzsubcarrier-spacing is 125 us long.

The first OFDM symbol(s) of a slot contains control information for theUE (User Equipment), the so called control region. This controlinformation can for example be downlink assignments or uplink grants.

To reduce latencies a mechanism called mini-slots has been introduced inNR. A mini-slot is, as the name suggests, a slot that has fewer OFDMsymbols than a regular slot. Current agreements allow mini-slots oflength 2 to 14 OFDM symbols.

Similar to a slot, the first OFDM symbol(s) of a mini-slot containscontrol information. Thus for a UE to be able to be scheduled usingmini-slots, it must monitor the control region of every possiblelocation of the mini-slot. For example, if the mini-slot comprises oftwo symbols out of one is the control region, the UE needs to monitorthe control region every second OFDM symbol.

NR also supports flexible bandwidth configurations for different UEs onthe same serving cell. In other words, the bandwidth monitored by a UEand used for its control and data channels may be smaller than thecarrier bandwidth. One or multiple bandwidth part configurations foreach component carrier can be semi-statically signalled to a UE, where abandwidth part consists of a group of contiguous PRBs. Reservedresources can be configured within the bandwidth part. The bandwidth ofa bandwidth part equals to or is smaller than the maximal bandwidthcapability supported by a UE.

The inventors of the inventions to be discussed herein, has, afterinsightful and inventive reasoning, envisioned and realized that therewill be a problem in that to allow a gNB (NR access point or basestation) to access the channel using mini-slots, UEs must be configuredto monitor the control region with a periodicity that equals themini-slot length. This is costly in terms of processing resources andpower consumption. Once the gNB has gained access to the channel, inmany cases scheduling with slot granularity is sufficient. Thus there isa need for a method to switch between the frequent monitoring of thecontrol region of mini-slots and the less frequent monitoring of thecontrol region of the regular slots.

The same problem may exist when a UE accesses a channel during Device toDevice (D2D) communication).

In view of the problems and shortcomings indicated above, there is aneed for an improved manner of monitoring a control channel that reducesthe power consumption and also the consumption of other resources.

SUMMARY

The inventors of the present invention have realized, after inventiveand insightful reasoning that there are envisioned problems relating tothe mini slots as discussed above.

This invention proposes a method a UE method for switching betweenmonitoring of the control region of mini-slots, e.g. every X=2 OFDMsymbols and monitoring of the control region of regular slots, e.g.every X=7 or 14 OFDM symbols. The method is based on that before the UEdetects a transmission from the serving gNB it monitors the controlregion of mini-slots. Once detecting a transmission from the serving gNB(and if configured to do so) it stops monitoring the control region ofmini-slots and starts monitoring the control region of regular slots.

It is therefore an object of the teachings of this application toovercome or at least mitigate one or more of the problems andshortcomings listed above and below by providing a method for use in aUser Equipment for example being configured to operate according to theNew Radio (5G) standard, said method comprising: monitoring a controlregion for mini-slots for a transmission; detecting a start of thetransmission; monitoring a control region of said transmission forregular slots; and monitoring the control region for mini-slots again.

In one embodiment the method further comprises determining atransmission length.

In one embodiment the method further comprises detecting that thetransmission has ended; and in response thereto monitor the controlregion for mini-slots again.

In one embodiment the method further comprises postponing the switchfrom monitoring the control region of mini-slots to monitoring thecontrol region of regular slots until a slot border.

In one embodiment the method further comprises receiving informationregarding if a particular slot (slot or mini-slot) is allocated fordownlink or uplink, and in case of uplink allocation, stoppingmonitoring of the control region for said slot and resuming monitoringin time intervals allocated to downlink transmissions.

In one embodiment the method further comprises adaptation of a bandwidththat is monitored.

It is also an object of the teachings of this application to overcome orat least mitigate one or more of the problems and shortcomings listedabove and below by providing a User Equipment for example beingconfigured to operate according to the New Radio (5G) standard andcomprising a controller configured to: monitor a control region formini-slots for a transmission; detect a start of the transmission;monitor a control region of said transmission for regular slots; andmonitor the control region for mini-slots again.

It is also an object of the teachings of this application to overcome orat least mitigate one or more of the problems and shortcomings listedabove and below by providing a computer readable storage medium encodedwith instructions that, when executed on a processor, perform the methodaccording to herein.

By allowing the UE to only monitor the control region of the mini-slotsbefore the gNB has gained access to the channel and then switching tomonitoring the control region of regular slots, the UE can both savepower and avoid being capable of frequent control region monitoringwhile receiving data. Where the latter can benefit a simpler UE designand lower cost.

Other features and advantages of the disclosed embodiments will appearfrom the following detailed disclosure, from the attached dependentclaims as well as from the drawings. Generally, all terms used in theclaims are to be interpreted according to their ordinary meaning in thetechnical field, unless explicitly defined otherwise herein. Allreferences to “a/an/the [element, device, component, means, step, etc.]”are to be interpreted openly as referring to at least one instance ofthe element, device, component, means, step, etc., unless explicitlystated otherwise. The steps of any method disclosed herein do not haveto be performed in the exact order disclosed, unless explicitly stated.

BRIEF DESCRIPTION OF DRAWINGS

The invention will be described in further detail under reference to theaccompanying drawings, in which:

FIG. 1A shows a schematic overview of a UE according to one embodimentof the teachings of this application;

FIG. 1B shows a schematic overview of the components of a UE accordingto one embodiment of the teachings of this application;

FIG. 2 shows a schematic view of an example UE system according to oneembodiment of the teachings of this application;

FIG. 3 shows a schematic view of a computer-readable medium according tothe teachings herein;

FIG. 4 shows a flowchart for a general method of controlling atelecommunications device according to the teachings herein;

FIG. 5 shows a schematic time view of a transmission according to oneembodiment of the teachings of this application;

FIG. 6 shows a schematic time view of a transmission according to oneembodiment of the teachings of this application; and

FIG. 7 shows a schematic view of a circuit arrangement for handling atransmission according to one embodiment of the teachings of thisapplication.

DETAILED DESCRIPTION

The disclosed embodiments will now be described more fully hereinafterwith reference to the accompanying drawings, in which certainembodiments of the invention are shown. This invention may, however, beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein; rather, these embodiments areprovided by way of example so that this disclosure will be thorough andcomplete, and will fully convey the scope of the invention to thoseskilled in the art. Like numbers refer to like elements throughout.

FIG. 1A shows a schematic overview of a telecommunications device orUser Equipment (UE) 100 according to one embodiment of the presentinvention. The UE may be a robotic tool, a smartwatch, a smartphone, aninternet tablet, a gaming device, or a (laptop) computer. In thefollowing the UE will be exemplified as being a smartphone 100.

The UE 100 comprises a presentation device 110 being able to outputand/or receive data. One example of such a presentation device is atouch display 110.

The touch display 110 a user provides input by touching the display,possibly on a virtual key 120A. Other manners of inputting data isthrough physical keys 120B. IN the example of FIG. 1A, the UE 100 hastwo virtual keys 120A and one physical key 120B, however, as would beunderstood, any number, shape and arrangement of keys depends on thedesign of the UE, and also the current execution context of the UE.

The UE 100 may also be arranged to receive and/or output haptic data,such as through a haptic presentation device 110, possibly beingincorporated in the touch display 110.

FIG. 1B shows a schematic view of the components of a UE 100. Acontroller CPU is configured to control the overall and also specificfunctions of the UE 100 such as by executing computer programinstructions loaded into or stored on a memory connected or being partof the controller. The controller may comprise one or more processors orother logic programmable circuits for combined or individual executionof a task or application. However, for the purpose of this applicationthey will be seen as being the one and same controller CPU. Thecontroller CPU is connected to a memory MEM for storing computerinstructions and also data to be processed by the computer instructionswhen executed by the controller CPU. The memory may comprise one orseveral memory circuits, possibly arranged in a hierarchy. One or moreof such memory circuits may be comprised in the controller CPU. For thepurpose of this application the memory circuits will be regarded as onememory MEM.

The controller CPU is also connected to a user interface UI forreceiving input from a user and for presenting data or other informationto the user. As discussed above, a display may be comprised in the userinterface UI.

The controller is also connected to a communications interface COM, suchas a Radio frequency interface. The RF interface may be configured tooperate according to a long range standard, such as a cellular networkstandard, for example a 5G standard. The RF interface may alternativelyor additionally be configured to operate according to a short rangestandard, such as a Bluetooth®, IEEE802.11b (WiFi™), IEEEE802.16,ZigBee™ or NFC™ (Near Field Communication) standard, for example a 5Gstandard.

The communications interface COM enables a first UE 100 to communicatewith a second UE (referenced 100A and 100B in FIG. 2 and as will bediscussed in greater detail with reference to FIG. 2) for receivingand/or transmitting visual and haptic data.

FIG. 2 shows a communication system arranged to operate according to the5G standard, in which a first UE 100A is communicating (as indicated bythe dashed arrows) with a second UE 100B. In one embodiment, thecommunication is effected through a base station gNB130. In oneembodiment, the communication is effected between the UEs in so-calledDevice-to-Device (D2D) communication, which is also supported by the5G-standard.

FIG. 3 shows a schematic view of a computer-readable medium as describedin the above. The computer-readable medium 30 is in this embodiment adata disc 30. In one embodiment the data disc 30 is a magnetic datastorage disc. The data disc 30 is configured to carry instructions 31that when loaded into a controller, such as a processor, executes amethod or procedure according to the embodiments disclosed above. Thedata disc 30 is arranged to be connected to or within and read by areading device 32, for loading the instructions into the controller. Onesuch example of a reading device 32 in combination with one (or several)data disc(s) 30 is a hard drive. It should be noted that thecomputer-readable medium can also be other mediums such as compactdiscs, digital video discs, flash memories or other memory technologiescommonly used.

The instructions 31 may also be downloaded to a computer data readingdevice 34, such as a smartphone or other device capable of readingcomputer coded data on a computer-readable medium, by comprising theinstructions 31 in a computer-readable signal 33 which is transmittedvia a wireless (or wired) interface (for example via the Internet) tothe computer data reading device 34 for loading the instructions 31 intoa controller. In such an embodiment the computer-readable signal 33 isone type of a transient computer-readable medium 30.

The instructions may be stored in a memory (not shown explicitly in FIG.3, but referenced MEM in FIG. 1B) of the smartphone 34. The smartphoneof FIG. 3 possibly being a smartphone as in FIGS. 1A and 1B. Theinstructions comprising the teachings according to the present inventionmay thus be downloaded or otherwise loaded in to a UE 100 in order tocause the UE 100 to operate according to the teachings of the presentinvention.

References to computer program, instructions, code etc. should beunderstood to encompass software for a programmable processor orfirmware such as, for example, the programmable content of a hardwaredevice whether instructions for a processor, or configuration settingsfor a fixed-function device, gate array or programmable logic deviceetc.

The invention will now be described based on the flowchart in FIG. 4showing a flowchart for a general method according to herein.

Before detecting any transmission burst (TB in FIGS. 5 and 6), such asfrom the gNB, the UE 100 monitors 410 the control region of mini-slots(MS in FIGS. 5 and 6). The transmission detection can be done e.g. bycorrelation to a known reference signal or preamble such as e.g. DMRS(Demodulation Reference Signal), CSI-RS (Channel StateInformation-Reference Signals), PSS, or SSS (Primary or SecondarySynchronization Signals) or by decoding a common channel, e.g. C-PDCCH(common physical downlink control channel) or PBCH (physical broadcastchannel). The periodicity at which the control region of mini-slotsoccur is given to the UE 100 as part of higher layer signaling, forexample RRC signaling, either dedicated or broadcast. In one embodiment,it is during every 2^(nd) OFDM slot. The transmission may also be from asecond UE 100 if D2D communication is used. The examples herein will,however, focus on the transmission from a gNB.

Upon detection 420 of a transmission from the gNB, the UE 100 optionallydetermines 430 the length of the transmission burst from the gNB. Thetransmission detection can be done e.g. by correlation to a knownreference signal or preamble such as e.g. DMRS (Demodulation ReferenceSignal), CSI-RS (Channel State Information-Reference Signals), PSS, orSSS (Primary or Secondary Synchronization Signals) or by decoding acommon channel, e.g. C-PDCCH (common physical downlink control channel)or PBCH (physical broadcast channel).

The transmission burst length determining 430 (which is optional) can bedone by reading explicit control information transmitted by the gNB one.g. C-PDCCH or it can be done by repeated transmission detection asoutlined above.

During the transmission burst, the UE 100 switches to monitoring 440 thecontrol region of regular slots (RS in FIGS. 5 and 6) instead ofmini-slots, if configured to do so. The configuration can include anoffset (relative the start of the transmission burst) at which theswitch from mini-slots to regular sized slots occur. The offset could bedetermined by the time point of LBT (Listen Before Talk) success,scheduling situation, data processing (encode and modulate) delay tomention a few examples. The periodicity of the monitoring has thuschanged.

In one embodiment the UE is configured to monitor the control channelwith a periodicity of once every 7^(th) OFDM symbol when monitoring forregular slots.

In one embodiment in FIG. 5, the first scheduled mini-slot is longerthan the unscheduled mini-slots prior to the start of the transmissionburst. The length of this longer mini-slot can be signaled dynamicallyusing a common control channel, e.g. C-PDCCH. Note that the use of acommon control channel conveys this information to all UE 100 s, notonly the ones scheduled in the mini-slot. Another option is that it canbe signaled through higher layer signaling, e.g. RRC signaling, that thefirst scheduled mini-slot of all transmission burst s extends to thenext slot border. This approach uses less overhead in terms of controlregion, but it requires more involved signaling and/or configurations.To avoid re-encoding the data, simple aggregation of each mini-slot datablock could be adopted by maintaining the same code rate. FIG. 5 thusshows one example of how the UE switches between control regionmonitoring for mini-slots and regular slots. In this embodiment thefirst scheduled mini-slot is longer than the minimum length of theunscheduled mini-slots prior to the start of the transmission burst. Inthis embodiment the UE is configured to monitor the control region formini-slots, every two OFDM symbols for example. And, as the UE detects atransmission, the UE then reads C-PDCCH and determines the length of thefirst scheduled mini-slot. Alternatively it may be configured throughRRC that the length of the first scheduled mini-slot extends to the slotborder.

The UE then starts monitoring the control region on the first OFDMsymbol in every slot. However, the UE may be configured to skipmonitoring the control region in the slot it knows is an UL slot. Thiscan be determined by reading C-PDCCH in the previous slot. Alternativelyit may be stipulate by a fixed pattern through RRC signaling.

If the UE skips monitoring for an UL slot, the UE resumes monitoring thecontrol region on the first OFDM symbol in every slot after the UL slot.

As the UE determines that the transmission burst has ended, the UEresumes monitoring of the control region of mini-slots. In oneembodiment, the UE determines that the transmission burst has ended bydetecting that the transmission has ended using transmission detectiontechniques. In one embodiment, the UE determines that the transmissionburst has ended by reading the length of the transmission burst inC-PDCCH. In one embodiment, the UE determines that the transmissionburst has ended by using a maximum transmission burst length.

In one embodiment as seen in FIG. 6, the length of the mini-slots doesnot change and the UE 100 postpones the switch from monitoring thecontrol region of mini-slots to regular slots until the slot border, or,if configured with an offset, to after the slot border. This approachuses more overhead in terms of control region, but requires lessinvolved signaling and/or configurations. FIG. 6 thus shows anotherexample of how the UE switches between control region monitoring formini-slots and regular slots. In this embodiment the scheduledmini-slots have the same length as the minimum length of the unscheduledmini-slots prior to the start of the transmission burst. In thisembodiment the UE is configured to monitor the control region formini-slots, every two OFDM symbols for example. And, as the UE detects atransmission, the UE continues to monitor the control region ofmini-slots until the next slot border. As a a slot border has passed,the UE starts monitoring the control region on the first OFDM symbol inevery slot.

However, the UE may be configured to skip monitoring the control regionin the slot it knows is an UL slot. This can be determined by readingC-PDCCH in the previous slot. Alternatively it may be stipulate by afixed pattern through RRC signaling.

If the UE skips monitoring for an UL slot, the UE resumes monitoring thecontrol region on the first OFDM symbol in every slot after the UL slot.

As the UE determines that the transmission burst has ended, the UEresumes monitoring of the control region of mini-slots. In oneembodiment, the UE determines that the transmission burst has ended bydetecting that the transmission has ended using transmission detectiontechniques. In one embodiment, the UE determines that the transmissionburst has ended by reading the length of the transmission burst inC-PDCCH. In one embodiment, the UE determines that the transmissionburst has ended by using a maximum transmission burst length.

In addition, the UE 100 may take or receive information (e.g.transmitted on C-PDCCH) regarding if a particular time interval (slot ormini-slot) is allocated for downlink or uplink. In case of uplinkallocation, the UE 100 stops monitoring of the control region for saidinterval. It then resumes monitoring in time intervals allocated todownlink transmissions.

Once the gNB transmission burst ends, the UE 100 switches back tomonitoring the control region of mini-slots. This can either bedetermined based on the optionally determined transmission burst lengthor detected using known reference signals as outlined above. Theprocedure then repeats for the next transmission burst.

In one aspect of the above embodiments, the switching between monitoringof slot and mini-slot control regions is augmented with adaptation ofthe bandwidth that is monitored in the respective cases. Usinghigher-layer signaling, a first bandwidth part is configured when the UE100 is monitoring the control region of mini-slots. After detecting thestart of gNB transmission, the UE 100 can be configured to switch to asecond bandwidth part when monitoring the slot control region. As anon-limiting example, the second bandwidth part is larger than saidfirst bandwidth part.

In another aspect of the above embodiments, the gNB configuration, usedfor configuring the UE, also enables or disables monitoring of certainDCI (Downlink Control Information) formats for the respective cases ofmini-slot and slot control regions. For example, monitoring of certainDCI formats may be disabled for the mini-slot control region when thereis no gNB DL activity, in order to reduce PDCCH decoding complexity.Utilizing the teachings herein, a UE will be able to detect and decodeDCI faster and while reserving resources.

The invention will now be described based on the circuit overview ofFIG. 7. Before detecting any transmission burst (TB in FIGS. 5 and 6),such as from the gNB, the UE 100 comprises a circuit 710 for monitoringthe control region of mini-slots (MS in FIGS. 5 and 6). The transmissiondetection can be done e.g. by correlation to a known reference signal orpreamble such as e.g. DMRS (Demodulation Reference Signal), CSI-RS(Channel State Information-Reference Signals), PSS, or SSS (Primary orSecondary Synchronization Signals) or by decoding a common channel, e.g.C-PDCCH (common physical downlink control channel) or PBCH (physicalbroadcast channel). The periodicity at which the control region ofmini-slots occur is given to the UE 100 as part of higher layersignaling, for example RRC signaling, either dedicated or broadcast. Inone embodiment, it is during every 2^(nd) OFDM slot. The transmissionmay also be from a second UE 100 if D2D communication is used. Theexamples herein will, however, focus on the transmission from a gNB.

For detection of a transmission from the gNB, the UE 100 comprises acircuit 720 for detection of a transmission. The UE may also optionallycomprises a circuit 730 for determining the length of the transmissionburst from the gNB. As stated above, the transmission detection can bedone e.g. by correlation to a known reference signal or preamble such ase.g. DMRS (Demodulation Reference Signal), CSI-RS (Channel StateInformation-Reference Signals), PSS, or SSS (Primary or SecondarySynchronization Signals) or by decoding a common channel, e.g. C-PDCCH(common physical downlink control channel) or PBCH (physical broadcastchannel).

The transmission burst length determining (which is optional) can bedone by reading explicit control information transmitted by the gNB one.g. C-PDCCH or it can be done by repeated transmission detection asoutlined above.

The UE also comprises a circuit 740 for monitoring control regions ofregular slots so that during the transmission burst, the UE 100 mayswitch to monitoring the control region of regular slots (RS in FIGS. 5and 6) instead of mini-slots, if configured to do so. The configurationcan include an offset (relative the start of the transmission burst) atwhich the switch from mini-slots to regular sized slots occur. Theoffset could be determined by the time point of LBT (Listen Before Talk)success, scheduling situation, data processing (encode and modulate)delay to mention a few examples. The periodicity of the monitoring hasthus changed.

In one embodiment the UE is configured to monitor the control channelwith a periodicity of once every 7^(th) OFDM symbol when monitoring forregular slots.

The UE also comprises a circuit 750 for detecting end of a transmission,upon which the circuit for monitoring mini slots 710 is again activated.

The invention has mainly been described above with reference to a fewembodiments. However, as is readily appreciated by a person skilled inthe art, other embodiments than the ones disclosed above are equallypossible within the scope of the invention, as defined by the appendedpatent claims.

1. A method for use in a User Equipment, said method comprising:monitoring a control region for mini-slots for a transmission; detectinga start of the transmission; monitoring a control region of saidtransmission for regular slots; and monitoring the control region formini-slots again.
 2. The method of claim 1, further comprisingdetermining a transmission length.
 3. The method of claim 1, furthercomprising detecting that the transmission has ended; and in responsethereto monitor the control region for mini-slots again.
 4. The methodof claim 1, further comprising postponing the switch from monitoring thecontrol region of mini-slots to monitoring the control region of regularslots until a slot border.
 5. The method of claim 1, further comprisingreceiving information regarding whether a particular slot mini-slot isallocated for downlink or uplink, and in case of uplink allocation,stopping monitoring of the control region for said slot and resumingmonitoring in time intervals allocated to downlink transmissions.
 6. Themethod of claim 1, further comprising adaptation of a bandwidth that ismonitored.
 7. The method of claim 1, wherein the User Equipment isconfigured to operate according to the New Radio (5G) standard.
 8. Anon-transitory computer readable storage medium encoded withinstructions that, when executed on a processor, perform a method foruse in a User Equipment, said method comprising: monitoring a controlregion for mini-slots for a transmission; detecting a start of thetransmission; monitoring a control region of said transmission forregular slots; and monitoring the control region for mini-slots again.9. A User Equipment comprising a controller configured to: monitor acontrol region for mini-slots for a transmission; detect a start of thetransmission; monitor a control region of said transmission for regularslots; and monitor the control region for mini-slots again.
 10. The UserEquipment of claim 9, being further configured to operate according tothe New Radio (5G) standard.